The War Department (WD) "Austerity" 2-8-0 is a type of heavy freight steam locomotive that was introduced in 1943 for war service. A total of 935 were built, making this one of the most numerous classes of British locomotive. The Austerity 2-8-0 was based on the LMS Class 8F, which until that point had been the government's standard design. Various modifications were made to the 8F design by R.A. Riddles in order to prioritise low cost over design life. The North British Locomotive Company of Glasgow built 545 and Vulcan Foundry 390. After the war, 200 were sold to the LNER, who classified them as "Class O7" and numbered them 3000–3199. In 1948, 533 more were purchased by the British Transport Commission. With the formation of British Railways, the 733 locomotives were renumbered into the 90000–90732 series, and of these 123 remained in service at the start of 1967. Two locomotives continued to be held in WD stock, seeing service on the Longmoor Military Railway in Hampshire. One WD 2-8-0 has survived in preservation at the Keighley & Worth Valley Railway.